Fiberglass and resin really stick to foam??

[jimbo69ny]

Hello,

I just started a foamy build. I am working on the floor now.

I just have a hard time believing that resin and fiberglass is going to stick to these slick rigid foam boards. Is there any special trick to it? I saw one thread where a guy poked a bunch of holes in the foam board so it would absorb the resin. He said the board consumed a lot of the resin when he did that.

Any tips or tricks? I have minimal experience with fiberglass and resin. From what I have experienced, it seems like I am going to need A LOT of layers to make it strong.

I have seen some people use wood glue and painting cloth. I dont like that, it seems like a ton of work. Could I use painters cloth and resin? Fiberglass is really expensive and I feel like I am going to need a TON of it!

Thanks!

[EZ]

Burt Rutan designed and bult many aircraft using the fiberglass/epoxy over foam core method. I hope it sticks! I understand how it might seem it won't. I have used a lot of epoxy but never over foam. Others will chime in with practical experience I am sure.

[tony.latham]

EZ is spot on.

Fiberglass is really expensive and I feel like I am going to need a TON of it!

It's about $6.50 a yard. You'll need about... 10 yards or so...

Save some money and use polyester resin. It'll melt your foam and be a disaster. (Use epoxy.)

Tony

[KennethW]

I have build a foamie with canvas and paint. I think it is easier to work with then glass and resin. I feel the canvas and paint (PMF) work better as it is flexible. Fiberglass is hard and if it flex it cracks.

Sent from my Moto G (4) using Tapatalk

[John61CT]

Yes I thought the whole point of Foamies was that they are PMF, **not** fibreglass!

Lighter, more flexible and **so much** cheaper.

Regarding sticking, I always imagine the outer skin as pretty fully encapsulating the core.

Once that shell has hardened, it's sticking mostly to itself, and the foam core doesn't really have anyplace else to move to anymore.

Of course doing it wrong, and/or enormously strong forces in/from unanticipated directions can cause disaster, no matter the materials used.

[Pmullen503]

There is really no advantage to epoxy/glass over foam compared to canvas and glue. Having done lots of epoxy/glass (on boats over wood) and now canvas on a foamy trailer, I'd say the canvas is more forgiving.

[greygoos]

I believe the first foam trailer on here was covered in fiberglass but I am not sure if it was ever finished. There is also a very well documented build on here by KC, I dont remember the name of his build, I dont think he finished that one either but I am sure you can find them in the search above. I think its the Poet Creek Express. He could probably tell you all about fiberglass, resin and foam. Bottom line- build it the way you want.

[jimbo69ny]

EZ is spot on.

Fiberglass is really expensive and I feel like I am going to need a TON of it!

It's about $6.50 a yard. You'll need about... 10 yards or so...

Save some money and use polyester resin. It'll melt your foam and be a disaster. (Use epoxy.)

Tony

That is a long video!! Can you give me the cliff notes?

I think you misstyped. You told me to use polyester resin and it will melt my foam, then use epoxy. I assume you meant DONT use polyester resin and USE epoxy. Is that correct?

[jimbo69ny]

I have build a foamie with canvas and paint. I think it is easier to work with then glass and resin. I feel the canvas and paint (PMF) work better as it is flexible. Fiberglass is hard and if it flex it cracks.

Sent from my Moto G (4) using Tapatalk

DId you use the canvas, wood glue, then paint method? I have seen videos about that on youtube. I am worried about the finish. I really want this to look nice. How long have you had it? I also worry that the paint will break down and flake off over time.

What is PMF?

[tony.latham]

I think you misstyped. You told me to use polyester resin and it will melt my foam, then use epoxy. I assume you meant DONT use polyester resin and USE epoxy. Is that correct?

Excuse my facetiousness! Just make sure you use epoxy and not the cheap polyester because it will melt your foam.



T

[jimbo69ny]

Does anyone know if I can use canvas and resin instead of fiberglass and resin? I know I will have to add many layers in order to make it strong so maybe some fiberglass, some canvas? I have no idea how canvas interacts with resin.

Speaking of which, how many layers is sufficient?

[jimbo69ny]

I think you misstyped. You told me to use polyester resin and it will melt my foam, then use epoxy. I assume you meant DONT use polyester resin and USE epoxy. Is that correct?

Excuse my facetiousness! Just make sure you use epoxy and not the cheap polyester because it will melt your foam.



T

Ok epoxy resin and not polyester resin. Gotcha. Thanks!

[jimbo69ny]

There is really no advantage to epoxy/glass over foam compared to canvas and glue. Having done lots of epoxy/glass (on boats over wood) and now canvas on a foamy trailer, I'd say the canvas is more forgiving.

Could I use canvas and epoxy?

[Pmullen503]

Does anyone know if I can use canvas and resin instead of fiberglass and resin? I know I will have to add many layers in order to make it strong so maybe some fiberglass, some canvas? I have no idea how canvas interacts with resin.

Speaking of which, how many layers is sufficient?

Don't use epoxy with canvas. You'll use LOTS resin! One layer of 6 to 10 oz canvas with wood glue is enough.

Maybe you don't understand why you are building a foamy in the first place: Cheap, light, and easy. To get that you'll have to tolerate the rougher surface finish that more easily dents (though it will self heal in sun.)

If you want a hard, tough surface, then build with plywood and cover with either aluminum or epoxy/glass.

[jimbo69ny]

Does anyone know if I can use canvas and resin instead of fiberglass and resin? I know I will have to add many layers in order to make it strong so maybe some fiberglass, some canvas? I have no idea how canvas interacts with resin.

Speaking of which, how many layers is sufficient?

Don't use epoxy with canvas. You'll use LOTS resin! One layer of 6 to 10 oz canvas with wood glue is enough.

Maybe you don't understand why you are building a foamy in the first place: Cheap, light, and easy. To get that you'll have to tolerate the rougher surface finish that more easily dents (though it will self heal in sun.)

If you want a hard, tough surface, then build with plywood and cover with either aluminum or epoxy/glass.

I spent $15,000 on the battery that will be underneath the teardrop. I spent $700 on an Axle less Timbren suspension. Cheap isnt the top priority. Obviously I need to keep everything in check but lightweight is my top priority. My battery alone weighs 1330 lbs. TImbren is another 100 lbs. Aluminum frame is another 200 lbs. Fiberglass would be a drop in the bucket. lol